1. Field of the Invention
This invention pertains to an apparatus and method associated with exercise equipment, and particularly a treadmill, in a substantially weightless environment, such as exists in space flight activity.
2. Description of the Prior Art
Although an orbiting spacecraft or a spacecraft in free-fall is still obviously within the ambit of gravitational forces exerted by planets or other heavenly bodies, the gravitational exertion on the spacecraft and living beings within is balanced by centrifugal or other accelerative forces. This state is hereinafter called weightlessness. Such a state reduces many physical loads on living beings and absolutely precludes normal human locomotion.
The human body adapts to a wide range of environmental conditions. Researchers have proven that reduced locomotor activity reduces the cardiorespiratory capacity, muscle strength, mass and endurance, blood volume, and bone mineral concentration and strength. Thus, in an unstressed environment such as weightlessness, bone and muscle undergo rapid atrophy and cardio-respiratory capacity will be reduced such that after several months crewmen will no longer be able to walk on Earth.
Persons or other living beings must exercise in weightlessness as on Earth to maintain their cardiovascular, musculoskeletal, and other systems for normal activity on Earth. Human locomotion is an especially important exercise under these conditions. Primary concerns of such exercise are the foot ground forces and work level. These are absolutely dependent upon body weight, speed, grade and mode (walking or running). Since weight is a constant factor on Earth, locomotor forces and work level are not usually measured, instead they are indirectly determined by speed and grade. Body weight and grade are provided by gravitational forces which are nulled in space flight hence treadmills designed for Earth are unusable there.
Currently, the only exerciser capable of providing locomotor activity in a weightless environment of a spacecraft is a treadmill with provisions for providing an axial truncal force on an individual to simulate the body weight of the individual. Previous designs are only partially effective since actual forces and other stresses on the body are not being measured, are unknown and hence cannot be documented nor used to control the exercise. Also, means are not available to control equivalent grades.
A treadmill device that has been employed by the Union of Soviet Socialist Republics on space ventures sponsored by that country has employed elastic bungees and a harness to provide an adjustable, partly equivalent body weight or foot ground force against the tread. It is not believed that any such device includes a way of measuring that equivalent weight force. It is further believed that with such a device there is no elevation or grade provision or means for measuring or controlling grade. It is unknown but assumed that speed is measured and controlled.
Treadmill devices that have been employed by the United States on its space ventures provide mechanical means for applying forces estimated to be equivalent to body weight. These devices also have speed indicators for measuring the speed of the belt but heretofore, there has been no way to provide for and/or measure an equivalent grade. Without such information, neither forces nor work can be measured or controlled.
In addition, only passive treadmills have been used to date in the United States program and these require some minimum equivalent grade typically 10%, and this also limits their utility.
Therefore, it is a feature of this invention to provide a method of accurately simulating Earth locomotion in a weightless environment by measurement and control of essential parameters.
It is another feature of this invention to provide a small, lightweight apparatus for simulating locomotion in a weightless environment.
It is another feature of this invention to provide a method of measuring forces exerted on a body during locomotion.
It is another feature of this invention to provide an apparatus for measuring forces exerted on a body during locomotion.
It is another feature of this invention to provide a method for measuring and controlling the vertical foot ground force.
It is another feature of this invention to provide an apparatus for measuring and controlling the vertical foot ground force.
It is another feature of this invention to provide a method for producing, measuring, and controlling the equivalent grade.
It is another feature of this invention to provide an apparatus for producing, measuring and controlling the equivalent grade.
It is yet another feature of this invention to provide a means for determining locomotor mode by visual inspection.
It is yet another feature of this invention to provide improved method and apparatus for generating a requisite work rate by an individual during locomotion.
It is yet another feature of this invention to provide an improved apparatus of correlating the actual measured forces to known work rate level measurement units such as body weight and grade of the surface.